Thermaltake London 550W Power Supply Review

Efficiency, PFC and Voltage Regulation

Voltage Regulation

To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.

Voltage regulation was strong on the 3.3, 5 and minus 12 volt rails. On the 12 volt rail we saw the voltage start at 3.75% above what it should be, towards 100% load it tended closer towards 12 volts but the initial and end values are still too high in my opinion. The results are okay but could still be improved.

Power Efficiency

Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.

Efficiency conforms to 80 Plus Gold without a hiccup – no complaints here.

Power Factor Correction

Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).

PFC is strong enough for a unit of this calibre: I’ve seen better but I’ve also seen a lot worse. At the price point it does well.